U.S. status of particulates — Monitoring, modeling, background, trends, and standards

Publisher Summary Particulate matter (PM) has been measured in the United States as total suspended particulates (TSP) and as particles of diameter 10 microns or less (PM 10 ). The first national ambient air quality standards (NAAQS) for PM were established in 1971 and were based on health data and air quality data assembled by the Department of Health Education and Welfare in 1969. The monitoring method for PM in the United States is basically gravimetric, as opposed to nephelometer or beta gauge instruments. The reason for this is the ability to analyze a subset of filters for speciated compounds comprising the particulate mix. Such analyses are essential for control strategies and provide a better understanding of the dynamics of a regional or local particulate situation. Unfortunately, gravimetric methods incur high costs per sample and are manual methods. This has resulted in less than everyday sampling for the majority of the U.S. particulate networks.